Several previous studies have shown that .gamma.-aminobutyric acid (GABA) is a major inhibitory transmitter of the central nervous system and that disturbance of the excitation and inhibition interplay can lead to disease states such as Huntington's chorea, Parkinsonism, schizophrenia, epilepsy, depression, hyperkinesis and manic depression disorders. Certain compounds are known to be irreversible inhibitors of GABA-T and thereby to elevate brain levels of GABA, for example fluorinated methyl .gamma.-aminobutyric and .delta.-aminopentanoic acids and certain derivatives thereof as described in U.K. Patent Specification No. 2005264A.
European Patent Application No. 78100059.1 discloses inter alia .gamma.-monofluoromethyl-.gamma.-aminobutyric acid and pharmaceutically acceptable acid addition salts thereof. It is stated in said European Patent Application that the said compound inhibits glutamic acid decarboxylase and displays CNS activities, including sedative and antidepressant indications.
The compounds 4,4,4-trifluoro-3-amino-1-butanoic acid (i.e. beta-trifluoromethyl beta-alanine) and 4,4,4-trifluoro-3-amino-1-butyramide (i.e. beta-trifluoromethyl beta-alanine primary amide) have been reported in the literature (see, for example, H. M. Walborsky et al, J. Org. Chem. 21 (1956) at pages 538-539). As far as we are aware, no pharmacological activity has been reported for these known fluorinated methyl beta-alanine derivatives.